1. Field of the Invention
The present invention relates to a motor-driven hand-held tool, including a housing having a switching recess formed therein, an actuation member displaceably arranged in the switching recess for shifting a functional unit between different functional steps, and a functional step display arrangement having a read-out device mechanically connected with the actuation member and a display element provided in the housing for displaying an actual functional step.
2. Description of the Prior Art
Motor-driven hand-held tools have usually several functional units which, as required, are shifted between different functional steps such as, e.g. speeds or rotational directions. In order for a hand-held tool user to know, during an operation, at each moment, which functional step is set, many conventional hand-held tools are provided, mostly on the housing, with functional step display means that display an actual functional step, e.g., an actual speed, in form of a figure, letter, or symbol.
U.S. Pat. No. 6,364,580 discloses an electrical drilling and screw-driving tool provided on the housing upper side with a slide switch for switching over the gearing. The slide switch has an actuation member displaceably arranged in a housing recess for shifting between two switching positions, and a slide member which carries the actuation member and which is displaced along the inner side of the housing in the region of the housing recess. The actuation member carries, in the shifting direction of the slide switch, on one of its side a figure “1” and on the other of its side a figure “2.” Dependent on the switching position, either the figure “1” for the first speed or the figure “2” for the second speed is visible in the housing recess next to the actuation member, with the other figure being covered by the housing.
German Publication DE-2933355 discloses an electrical hand-held tool which is provided on a housing side with a change-over switch displaceable between two switching positions shown on the housing with figures “1” and “2.” The switching position of the change-over switch is transmitted to microcomputer that is connected with a display provided on the upper side of the housing. The display displays a speed number and an associated therewith, actual rotational speed and a number of other operational parameters.
The drawback of both solutions, those of U.S. Pat. No. 6,364,580 and German Publication DE-2933355, consists in that, on one hand, with mechanically operated functional step display means, only two functional steps can be displayed, and the display is effected by the actuation member. Therefore, the known functional step displays are not suitable for functional units having more than two functional steps, such as, e.g., a three-speed gearset. On the other hand, with many hand-held power tools, it is either very difficult to use the actuation member in such a way that a good visibility of the functional step display is insured or, vise versa, the functional step display, in particular during operation, is hardly visible in order to provide for good access to the actuation member. The drawback of electronically operated display means consists in high manufacturing costs of hand-held tool associated with the use of such display means. Moreover, vibrations and impacts that act on hand-held tool during operation, lead often to damage or disruption of operation of such display means.
Accordingly, an object of the present invention to provide functional step display means for motor-driven hand-held tools in which the drawbacks of the known display means are eliminated.
Another object of the present invention is to provide functional step display means with a good visibility of an identification mark and capable to display more than two functional steps.